1. Field of the Invention
The present invention relates generally to horizontal folding doors and more specifically to an improved horizontal folding door system, which provides increased rigidity when open.
2. Discussion of the Prior Art
The prior art includes at least two types of horizontal folding door systems. One type of horizontal folding door system includes two horizontal folding doors. Each horizontal folding door includes a plurality of folding door sections. The sections are approximately two feet in length. The plurality of folding door sections stack-up together, when closed. The drawback to this type of horizontal folding door system is that the plurality of folded door sections decrease the opening size. Another type horizontal folding door system includes two folding doors. Each folding door includes two folding door sections. The drawback to this type of horizontal folding door system is that the folding door sections are so large that they are subject to twisting. A sliding pivot point is formed on an end of a second door section, which makes the folding door unstable in an open position, during a wind gust.
Accordingly, there is a clearly felt need in the art for an improved horizontal folding door system, which provides increased rigidity when open, a maximum size door opening, and an improved locking system.
The present invention provides improved folding doors, which are more rigid when open than that of the prior art. An improved horizontal folding door system includes a first folding door, a second folding door, a trolley track, and at least two trolleys. The improved horizontal folding door system covers a large door frame opening for an airplane hanger or other building structure. The door frame includes a horizontal frame member terminated by a single vertical frame member on each end thereof. Each folding door includes a first door section and a second door section. One side of each first door section is pivotally attached to one vertical frame member and the other side of each first door section is pivotally attached to one side of a single second door section. The first door section preferably has a shorter length than the second door section. However, a door frame opening may also be covered with a single folding door instead of two.
The trolley track is attached to the horizontal frame member. At least one trolley is attached to a top of each second door section. Preferably, at least one locking pin extends from a top of each second door section and at least one locking pin extends from a bottom of each second door section. All the locking pins disposed on each second door section are preferably controlled by a single actuation device. A plurality of locking cavities must be formed in a floor of a building structure and a plurality of locking cavities are preferably formed in at least one overhead stud. A single locking cavity receives each locking pin.
Each door section preferably includes a bottom rail, two vertical rails and at least two horizontal girts. The bottom rail is terminated by a single vertical rail on each end thereof. Each vertical rail is structured to receive an end of the at least two horizontal girts. Each vertical rail is preferably structured to receive an end of a face plate. Reinforcing girts may be used to prevent the door sections from twisting. The reinforcing girts are retained in the two vertical rails. A second embodiment of each door section includes a front sheet, a rear sheet, a foam inner layer, and two end vertical rails. The front and rear sheets are retained, such that a space is created therebetween. Foam is blown into the space between the front and rear sheets to form a foam door section. A single vertical end rail is attached to each end of the foam door section.
Accordingly, it is an object of the present invention to provide an improved horizontal folding door system, which has increased rigidity when open.
It is a further object of the present invention to provide an improved horizontal folding door system, which has a maximum size door opening.
Finally, it is another object of the present invention to provide an improved horizontal folding door system, which has an improved locking system.
These and additional objects, advantages, features and benefits of the present invention will become apparent from the following specification.